Self-sustaining environmental control unit

ABSTRACT

A method and apparatus for housing an electronic device are provided. The apparatus includes an environmentally sealed chamber to protect the electronic device from harsh environments. The environmental conditions of the chamber are controllable using environmental controls which are controlled by digital processor with a stored program coupled with sensors. The digital processor may also control the application of power from an external interface. The apparatus also includes a self-contained power source running from a primary fuel. A control system is provided for managing power production and energy storage to maintain continuity of environmental conditions.

FIELD OF THE INVENTION

The invention relates to a method and apparatus for mounting electronicdevices and, more particularly, to protecting electronic devices fromharsh environments.

BACKGROUND OF THE INVENTION

Often it is desirable to use commercial off the shelf (COTS) electronicdevices, such as high speed computers, in harsh environments. Forexample, it may be desirable to use such electronic device in locationswhere environmental conditions, such as temperature, humidity, and airpressure, may not be suitable for electronic devices and power tosustain the environment may not be readily available.

Mechanically controlled Environmental Control Units (ECUs) exist whichare capable of controlling some environmental conditions, such astemperature, and can protect enclosed contents, such as COTS electronicdevices, from harsh conditions. However, such ECUs are without a digitalprogrammable controller and require an external power source. These ECUscannot operate without electric power from a power grid or vehicle andare not capable of modifying environmental control or managing internaland external power from a digital programmable controller.

SUMMARY OF THE INVENTION

In one aspect of the invention, an apparatus for housing an electronicdevice is provided. The apparatus comprises an environmentally sealedchamber having environmental conditions therein, wherein the chamberadapted to receive the device, environmental controls that control theenvironmental conditions, and a digital controller for monitoring theenvironmental conditions of the chamber and controlling theenvironmental controls.

In one embodiment, the sealed chamber is adapted to house at least oneof the group comprising electronic circuit boards, electronic modules,and electronic units. In another embodiment, the apparatus furthercomprises a self contained-power source configured to provide power tothe electronic device. In yet another embodiment, the digital controlleris further configured to regulate power generated by the self-containedpower source. The digital controller may also be configured to regulatepower received from an external power source.

In another embodiment, the apparatus further comprises a plurality ofsensors configured to detect environmental conditions and provideinformation regarding the environmental conditions to the digitalcontroller. The environmental controls may include mechanical controlsconfigured to alter environmental conditions inside the chamber, whereinthe mechanical controls are operated under control the digitalcontroller based, at least in part, on the information received from theplurality of sensors. In yet another embodiment, the digital controlleris configured to control the environmental controls based, at least inpart, on a standard operational profile which specifies desiredenvironmental conditions. In another embodiment, the apparatus furthercomprises an operator interface configured to provide information fromthe digital controller to an operator through an input/output device andto allow an operator to monitor and control the apparatus. The operatorinterface further comprises a data network interface configured to allowthe operator to remotely monitor and control the apparatus.

In another aspect of the invention, a method for housing an electronicdevice is provided. The method comprises acts of providing anenvironmentally sealed chamber having environmental conditions therein,the chamber adapted to receive the device, providing environmentalcontrols that control the environmental conditions, and providing adigital controller for monitoring the environmental conditions andcontrolling the environmental controls. In one embodiment, the methodfurther comprises an act of providing a self-contained power sourceconfigured to generate power for controlling the environmental controls.The digital controller may also regulate power generated by theself-contained power source and may regulate power received from anexternal power source. In another embodiment, the method may furthercomprise an act of providing a plurality of sensors configured to detectenvironmental conditions and provide information regarding theenvironmental conditions to the digital controller.

In yet another aspect of the invention a method for housing anelectronic device is provided. The method comprises acts of housing anelectronic device in an environmentally sealed chamber havingenvironmental conditions therein, controlling the environmentalconditions using environmental controls, and monitoring theenvironmental conditions of the chamber and controlling theenvironmental controls using a digital controller. In one embodiment,the method further comprises an act of using a self-contained fuelsource to provide power for controlling the environmental conditions andfor powering the electronic device. The method further comprises an actof regulating the power generated by the power source and an act ofstoring unused power generated by the power source. In anotherembodiment, the method further comprises an act of adjusting theenvironmental conditions inside the chamber based, at least in part, oninput received from a plurality of sensors inside the chamber.

In yet another aspect of the invention, an apparatus for housing anelectronic device is provided. The apparatus comprises anenvironmentally sealed chamber having environmental conditions therein,wherein the chamber is adapted to receive the device, environmentalcontrols for controlling the environmental conditions, and aself-contained power source adapted to generate power for controllingthe environmental conditions of the chamber. In one embodiment, thesealed chamber is adapted to house at least one of the group comprisingelectronic circuit boards, electronic modules, and electronic units. Inanother embodiment, the apparatus further comprises a digital controllerfor monitoring the environmental conditions and controlling theenvironmental controls. The digital controller may be configured toregulate power generated by the self-contained power source. The digitalcontroller may also be configured to regulate power received from anexternal power source. In one embodiment, the apparatus furthercomprises a plurality of sensors configured to detect environmentalconditions and provide information regarding the environmentalconditions to the digital controller. The environmental controls mayinclude mechanical controls configured to alter environmental conditionsinside the chamber, wherein the mechanical controls are operated undercontrol the digital controller based, at least in part, on theinformation received from the plurality of sensors.

Each of the above disclosed aspects and embodiments may be used andapplied separately and independently, or may be applied in combination.Description of one aspect of the invention is not intended to belimiting with respect to other aspects of the invention. These and otheraspects and embodiments of the invention are described below in greaterdetail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram of a self-sustaining environmental controlunit for COTS electronics at the circuit board level, according to oneembodiment of the invention;

FIG. 1B is a block diagram of a self-sustaining environmental controlunit for COTS electronics at the module level, according to oneembodiment of the invention;

FIG. 2 is a block diagram of a self-sustaining environmental controlunit, for COTS electronics at the unit level according to one embodimentof the invention;

FIG. 3 is a block diagram of a self-sustaining environmental controlunit in a mobile enclosure, according to one embodiment of theinvention;

FIG. 4 is a logical diagram of the self-sustaining environmental controlunit of FIG. 3.

FIG. 5 is a block diagram of a control system for a self-sustainingenvironmental control unit, according to one embodiment of theinvention;

FIG. 6 is a block diagram of a stoichiometry management system accordingone embodiment of the invention;

FIG. 7 is a block diagram of a fuel subsystem according to oneembodiment of the invention;

FIG. 8 is a block diagram of a waste management subsystem according toone embodiment of the invention;

FIG. 9 is a block diagram of an energy storage subsystem according toone embodiment of the invention;

FIG. 10 is a block diagram of a power supply subsystem according to oneembodiment of the invention;

FIG. 11 is a block diagram of a conditioned air supply system accordingto one embodiment of the invention;

FIG. 12 is a block diagram of power distribution subsystem according toone embodiment of the invention;

FIG. 13 is a power management timeline for power management in aself-sustaining environmental control unit, according to one embodimentof the invention.

DETAILED DESCRIPTION

As the clock speeds of electronic components, such as microprocessors,increase and the size of the semiconductor junctions of such componentshave decreased, the electronic devices have become more sensitive toenvironmental conditions, such as temperature. For example, somecommercial-off-the-shelf (COTS )computer circuit boards operate in atemperature range from 10 degrees Celsius to 40 degrees Celsius. As willbe discussed below in greater detail, COTS electronics may come in avariety of forms. For example, COTS electronics may be incircuit-board-level form, module-level form, or unit form.

It is often desirable to operate these electronic devices in harshenvironments. For example, some military applications may require use ofelectronics in the field. Other applications may include cellularnetworks, remote broadcasting equipment, and homeland securityapplications, in which electronic devices must be operated from avehicle, such as a remote broadcasting studio, mobile shelters, a motorhome, or an airplane. Additionally, these harsh environments often lacka power source for supplying power to the electronic devices.

A self-sustaining environmental control unit (SECU) may be provided,which runs directly on fuel. For example, when external power is notgenerally available or when a backup power source is required, then aSECU may be configured to run directly on fuel in conjunction with orexclusively from natural energy conversion subsystems. The SECU includesa digital programmable controller with sensors to manage theenvironmental conditions of the electronics contained within the SECU.The digital programmable controller may run a stored program and mayhave an input/output interface for an operator to read conditions,obtain a history of conditions, modify variables and controlenvironmental conditions. Thus, an operator may use the SECU to functionwith COTS electronics in harsh environments where external electricpower, such as national electric grid power or external generator is notavailable. The digital programmable controller may match the electricpower load to the available power. It may also anticipate futureelectric loads from sensor trend projections and configures powergenerating equipment to provide the power at the time it is needed.

One example of self-contained power source that may be used to operatethe SECU directly from fuel is a fuel cell. Any type of fuel cell, suchas a permeable exchange membrane (PEM) fuel cell, a solid oxide fuelcell (SOFC) or a direct methanol fuel cell (DMFC), may be used. Suchfuel cells are capable of generating electricity to power from chemicalreactions. Unlike internal combustion engines, fuel cells produce littlenoise, are environmentally friendly, and produce little heat, allowingthem to be used in close proximity to electronic equipment. Also becausefuel cells are direct current devices, they have low electromagneticradiation, which is also desirable for operation close to electronicequipment.

Power sources other than fuel cells may also be used. For example, solarpower generated from solar panels may be used, or wind power may beused. It should be appreciated that any electric power source which iscompatible with electronics and people may be used.

One embodiment of the invention, in which a SECU is powered by one ormore fuel cells, is shown in FIG. 1A. It should be appreciated thatother power sources could be used in place of the fuel cells. Forexample, solar panels or wind turbines may be used. FIG. 1 shows a SECU100, which includes a fuel system 101 which stores fuel, such ashydrogen or methanol, for the fuel cell. It should be appreciated thatthe type of fuel stored by fuel system 101 will depend on the type ofpower source used by the SECU. SECU 100 also includes a fuel input 115for providing fuel to the SECU.

Fuel Cell system 103 includes a fuel cell stack for generatingelectricity using fuel from fuel system 101. Fuel cells may often not becapable of powering electronic loads by themselves. For example, fuelcells may have a time lag from when power is called for to when it isavailable. Furthermore, the supply voltage may vary over a wide range.At cold temperatures, a long period of time may be consumed before fullpower is available. Additionally, the fuel cell may need to generatepower to heat itself in cold temperatures and cool itself in hottemperatures. Moreover, because fuel cells use oxygen in the air in achemical reaction to generate electricity, air pressure may affect thesupply and concentration of oxygen available to the fuel stack.Furthermore, the efficiency of certain types of fuel cells, such as PEMfuel cells, may be affected by impurities in the air. Also, impuritiesin the fuel provided to the fuel cell may also affect fuel cellefficiency. Thus, a control system 105 is provided to regulate the powerproduction of the fuel cell, interface with any external power sources,and apply power to the electrical load. Control system 105 may usestored power operational curves and monitor and chart internalenvironmental conditions to anticipate future power needs.

SECU 100 also includes environmental controls 107 which control theenvironmental conditions inside enclosure 109 of SECU 100. Environmentalcontrols may include for example, heating controls, ventilationcontrols, and air conditioning controls. In aviation applications, theSECU may include additional controls for regulation of air pressure andhumidity. SECU 100 also includes an enclosure 109 for housing electronicdevices. Enclosure 109 is environmentally sealed. An example of anenclosure suitable for use is disclosed by Vos, et. al. in U.S. Pat. No.6,330,152, which is hereby incorporated by reference in its entirety.Enclosure 109 may include backplane connectors 111 for mechanicallymounting COTS electronic devices, such as circuit boards. However, manyother ways of mounting electronic devices in enclosure 109 may be used,such as module-level mounting of electronic devices. For example, FIG.1B shows another embodiment, in which enclosure 109 includes shelves formounting electronic modules. A module may be an encapsulation of one ormore circuit boards with embedded cooling capability. The encapsulationmay protect the electronics from adverse air pressure changes and shockand vibration. Using module-level COTS devices in the SECU may beuseful, for example, in aviation applications where the enclosure 109may be opened for reconfiguration during operation of the COTS devices.The module may receive power from a cable raceway in SECU 100. Themodule surface may include a portion for heat exchange, a portion forcables and connectors, and a portion for mechanical mounting. SECU 100may also include an external power interface 113, for interfacing withother power sources such as external grid power, a solar power source,or a wind power source.

Another embodiment of the invention is shown in FIG. 2. FIG. 2 shows amobile SECU 200 which is designed to withstand the elements of harshenvironments directly. Similar to the embodiment of FIG. 1, FIG. 2includes a fuel system 101, a fuel cell system 103, a control system105, and environmental controls 107. SECU 200 also includes a rack formounting different modules. Modules may be hardened to withstandenvironments on their own so that an enclosure is not needed to housethe modules. All heating, cooling, and shock mounting is incorporatedinside each modules. Modules may be mounted and replaced to customizeSECU 200 for a particular purpose. SECU 200 shown in FIG. 2 iscustomized as a node server for a wireless repeater data network,intended to server smaller units (not shown) from a short range linkconnected through a long range link in SECU 200. As such, the modules inFIG. 2 include a computer system 201 a, a short range network radio 201b, and a long range network radio 201 c. Radio signal carrying data fromthe long rage radio connect the server to an external network, while theshort range radio connects nearby mobile units to the server. It shouldbe appreciated that SECU 200 may be customized in many other differentways by using different modules, as the invention is not limited in thisrespect.

Modules may be standardized so they can be affixed structurally to oneanother. For example, a module may have four mounting holes at themodule corners. A single threaded rod can be used to assemble themodules into a single structure. Alternatively, the modules could bebolted to one another in a cascaded arrangement.

As mentioned above, a module may be a self-contained encapsulation ofone or more circuit boards. Each module may include a channel designedto move air across heat sensitive components. Air volume and temperaturemay be regulated by SECU 200. Sensors may be embedded in each module toallow SECU control system 105 to keep the right amount of conditionedair within each module. The modules may also have there own embeddedcooling capability. For example, a solid-state heat pump can movethermal energy into and out of modules using heat sinks attached to themodule surface. Alternatively, a small fan may impinge air on microchipheat sinks, increasing heat transfer capacity within the module. Airflow in SECU 200 can then remove heat from the other side of the module.A module may also include its own power supply. Electrical connectionsmay be made by way of connectors mounted on one side of the module.Cable raceways of SECU 200 may provide power and signal paths betweenthe modules.

Another embodiment of the invention is depicted in FIG. 3. FIG. 3illustrates a SECU 100 adapted for a mobile environment. In FIG. 3, atrailer provides mobility for the electronic equipment housed in SECU100. The trailer may include an air intake 301 for providing air used bythe fuel cells. Trailer 300 may also include another power source suchas solar panels 300, which interface with the external power input ofSECU 100 and a waste discharge unit used to hold waste discharged fromthe SECU.

It should be understood that the embodiment of FIG. 3 may be used inmobile environments other than a trailer. For example, the embodimentcould be used in a truck, airplane or marine vessel. In addition, SECU100 could also be installed in a cell tower or unmanned fixed shelter orbuilding structure which is not designed for human habitation, lackingheat, ventilation, plumbing and external electric power. If, forexample, the mobile environment in which the SECU is used is anairplane, solar panels may be replaced by the airplane's engines as asecondary power source. Alternatively, the airplane's engines may be theprimary power source when the airplane is operating and the fuel cellsmay be the primary power source when the airplane is not operating. Whenthe airplane is not operating, the interior will not be environmentallycontrolled. Thus, it is important for the fuel cell to provide thenecessary power to hear or cool the electronic devices, as the interiorof the airplane will be subject to external extremes. Additionally, theelectronic devices may require humidification or drying. As a result,the fuel cell may provide power for the electronic equipment to operateeven though the airplane crew is not present and engine power is notavailable. Thus, the SECU unit may improve aircraft performance byeliminating the need for the crew to boot start the system from a coldsoak or cool the unit from a hot soak prior to applying power andbrining up the system.

It should be appreciated however, that the exact physical form andlocation of each of the logical components shown in FIG. 3 may varydepending on the mobile environment in which it is situated.

A high-level logical system diagram of a SECU that is suitable for usein a mobile enclosure (e.g., the trailer of FIG. 3) is shown in FIG. 4.It should be appreciated that the system of FIG. 4 may be applied tomany different types of mobile environments, such as, for example, thosediscussed above with respect to FIG. 3. It should also be appreciatedthat the exact physical form and location of each of the logicalcomponents shown in FIG. 4 may vary depending on the mobile environmentin which it is situated.

FIG. 4 shows a SECU 400 which includes external interfaces 451, controlsystem 453, environmental enclosure 455, and ECU mechanical controls457. External interfaces 451 interface the mechanical controls 457 withthe host vessel. For example, the host vessel could supply externalpower, water, or air to the mechanical controls 457 of SECU 400, usinginterfaces 451. It should be appreciated that the host vessel may be anytype of vessel, such as an automobile, truck, tank, airplane, or marinevessel. The quality and quantity of the interfaces may be monitored bysensors of control system 453 as well as controlled by the controlsystem. Thus, control system 453 may adjust, for example, the qualityand quantity of internally generated power in response to the amount ofexternally generated power which is available. The power may then besupplied to the enclosure for heating, cooling, humidifying, or dryingof the enclosure.

FIG. 5 is a block diagram which illustrates generally the function ofcontrol system 105. Control system 105 includes a single board computer(SBC) 401 which executes control system software to process informationreceived from a sensor subsystem 409 and make appropriate modificationsto other components of control system 105 and the SECU. A user interface405 allows a user to interact with the control system, and may includefunction keys, a display, or other controls. Network interface 407allows SBC 401 to send and receive data over a network, so that SBC canbe controlled or programmed remotely.

SBC 401 may be hardened circuitry, designed to operate in harshenvironments. Thus, the SBC may operate outside the environmentallycontrolled enclosure of the SECU, although in practice the SBC may belocated in enclosure 109 of the SECU. Accordingly, SBC 401 may bedesigned to have low computational performance requirements in exchangefor rugged environmental performance. For example, suppose that the SECUincludes fifty sensors, each of which needs to be strobed five times persecond on average. An average sensor may require approximately fourthousand machine-level instructions to be executed each time the sensoris strobed. Thus, an SBC which is capable of executing fifty millioninstructions per second (MIPS) may be adequate.

User interface 405 provides a system operator with access to controlsystem 105. User interface 405 may include function keys and displaywhich allow an operator to manage the control system. Also, userinterface may include controls which allow an operator to manuallyoverride control system software and directly affect an operation of theSECU. Network interface 407 allows an operator to perform the samemanagement operations remotely, using a data network.

Sensor subsystem 409 includes a plurality of sensors for monitoringvarious attributes of the SECU. Sensors may be located in any module orsubsystem of the SECU, including fuel subsystem 101, power productionsubsystem 103, power source selection 411, energy storage subsystem 413,power supply subsystem 415, environmental controls 107, and enclosure109. Such sensors may include, for example, sensors to monitor theenvironmental conditions (e.g., temperature, humidity, air pressure) ofenclosure 109, fuel cell sensors for measuring air purity and fuelpurity, sensors for monitoring the amount of energy stored by energystorage subsystem 413, sensors for monitoring the quantity of fuelstored by fuel system 101, and sensors for power management purposes,such as monitoring power quality. It should be appreciated that thesetypes of sensors are given only by way of example as the invention isnot limited in this respect.

A standard operational profile 403 is provided to SBC 401. The standardoperational profile is a calibrated curve of operating points coveringtemperature, humidity and pressure and may be generated for a specificcombination of power sources. For example, a profile may be generatedfor a DMFC with an external solar power interface. That is, the profiledefines, for a particular combination of power sources, what powerproduction should be for each power source to meet particulartemperature, humidity, and pressure requirements, given the load of theelectrical equipment. For example, in a PEM fuel cell an electrochemicalstoichiometry relationship exits between fuel, oxidant (e.g., air) andelectric power production. This relationship is sometimes referred to asa polarization curve. The control system may use such polarizationcurves as a reference for comparing current settings and determiningwhat should be adjusted to bring the SECU operating point close to thestandard operational profile.

FIG. 12 illustrates how power may be delivered to various subsystems ofthe SECU. Power may be generated internally from internal power source1101 and may also be received from an external power source 1105. Storedpower from energy subsystem 1113 may also be used to provide power toSECU subsystems and electronic devices. Control system 1103 monitors howmuch power is available from each power source and determines how muchpower to supply from each power source to each subsystem which requirespower. For example, if using a fuel cell stack to generate powerinternally, a warm-up period may be needed before the fuel cells areavailable. During this period, control system 1103 may direct power froman external source, if available, or the energy storage subsystem topower the mechanical controls 1111 and COTS electronics 1109 in theenclosure. When internally generated power becomes available (i.e.,after the fuel cell warm-up period), then control system 1103 maydecrease power output from energy storage subsystem 1113 and externalpower source 1105.

FIG. 13 is an example of power management timeline, illustrating how thecontrol system uses power from different sources. At time 5, theinternal power source is turned on. However, in this example a warm-upperiod is required before the internal power source begins to generatepower. Thus, between time 5 and 6, the SECU relies on power from theexternal power source and the storage subsystem. It should be noted thatthe control system may take advantage of beneficial conditions such assunshine when using solar cells or wind when using turbines to diminishor extinguish a fuel cell to conserve fuel resources. The external powersource may be, for example, a solar panel, which is available in varyingcapacity. At time 6, the internal power source becomes available and thecontrol system begins to use power output from the internal source incombination with power from the external source. The controller knowsthe SECU power needs, knows what is available from the solar source andcan draw an optimal fuel cell power level supplementing naturalvariances from the source with power from the storage subsystem so thatthe averages from all sources is a steady supply of electric power formechanical controls and COTS electronics. Any excess power may be usedto replenish the energy storage subsystem, keeping it at optimalreserve.

As shown in FIG. 6, control system 105 controls fuel reformer 601 andconditioned air supply system 500 to control the amount of air and fuelsupplied to fuel cell stack 501. In this manner, the power production ofthe fuel cell stack may be controlled. Electric power output by fuelcell stack 501 may then be delivered by a switching network 603 to anelectrical load 605, which may include a power supply subsystem,mechanical controls, or energy storage subsystem.

On power-up, SBC 403 may be powered by an energy storage system 113,which will be discussed below in greater detail. Upon power-up SBC 403may determine if the SECU has been set by an operator, for example,using user interface 405, to use internal or external power. If the SECUis set to use external power, SBC 401 will use sensor subsystem 409 todetermine if the power quality is good. If the power quality is good,SBC 401 will power-up the environmental controls 107. If the powerquality is not good, SBC 401 will inform the operator of the poor powerquality using user interface 405.

If the operator has set the SECU to use internal power via userinterface 405, power from the energy storage subsystem may be used tostart operation. If insufficient power is available, the operator mayconnect an external emergency power source 417 to the energy storagesubsystem. External emergency power source 417, may be for example, abattery of sufficient capacity. Once the control system is powered up,sensors may collect data so that environmental controls 107 may beginoperating.

It is important that the sensors collect data before operation of theelectronic devices in the enclosure so that the electronics may notbegin operation if the environmental conditions of the enclosure are notsuitable for operation of the electronic equipment. For example, if thetemperature of the enclosure is above the maximum permissibletemperature, powering up the electronic devices may destroy the devicebefore the environmental controls are given sufficient time to cool theenclosure.

Control system 105 may then look at the last sensor values stored inmemory and compare these values to the current conditions. If the lastsensor values were good, control system 105 may set the SECU from thosesettings. If the sensor values were not good, then those settings may beavoided.

If sensor measurements are good and the SECU is set to use internalpower, control system 105 may then start fuel system 101. As shown inFIG. 7, fuel system 101 may include a fuel storage reservoir 703 and afuel reformer 701. Fuel system 101 is checked to see if there is enoughfuel to start and continue operation of the SECU. The fuel reformer maybe used to convert primary fuel to an intermediate form suitable for useby the power source (e.g., a fuel cell). For example if using a PEM fuelcell, the fuel reformer may convert a liquid or gaseous fuel to a purehydrogen gas for use by the fuel cell. Fuel reformer 701 may break downthe fuel by mixing it with steam at a certain pressure and temperaturein reformer enclosure 705 to break the fuel into a hydrogen stream,carbon monoxide, and water vapor. The concentration of impurities in thehydrogen stream can be controlled by the pressure and temperature ofgases in reformer enclosure 705 and the flow rate of gases into reformerenclosure 705. Such parameters may be controlled by reformer controlsystem 707 via control system 105. Sensors in the fuel reformer monitorthe byproducts of the fuel reformation process to ensure that anyimpurities in the fuel supplied to the power source are withinacceptable tolerances and that the fuel supplied to the power source isat an appropriate temperature and pressure. It should be appreciatedthat a fuel reformer may not be necessary. For example, if using a DMFC,it may not be necessary to use a fuel reformer. Fuel system 101 may alsoinclude a waste level management subsystem. As mentioned above, the fuelreformer may generate waste water and impurities such as carbonmonoxide. The fuel reformer may also generate excess heat producedduring reformation of fuel. Moreover, the fuel cell stack may alsogenerate waste water and excess heat. A waste level managementsubsystem, shown in FIG. 8, may be provided to discharge waste and putthe excess heat and water to use for the SECU.

As shown in FIG. 8, fuel stack 501 receives air and fuel and generateselectric power and waste water. The waste water may be stored in ahumidification reservoir 511 used to humidify the air provided to thefuel cell stack or enclosure of the SECU. A mechanical pump 801 may pumpexcess water from humidification reservoir 511 and discharge the water.Likewise, fuel reformer 701 receives fuel and generates as byproductssteam and carbon monoxide. A condenser and heat extractor 805 maycondense the steam to water, where it may be provided to humidificationreservoir 511 or discharged. The heat energy may be reclaimed andprovided to heat energy reclamation block 803 where it may bedistributed to other subsystems or enclosure 109.

Next, control system 105 may open a pressure regulator to send the fuelfrom fuel system 101 to power production system 103. Power productionsystem 103 includes the internal power source or power sources for theSECU. For example, power production system 103 may include a stack offuel cells. Alternatively, if an internal power source of the SECU iswind power, power production system 103 may include a wind turbine.Control system 105 may then set up power source selection subsystem 411to transfer power produced by power production system 103 to energystorage subsystem 413.

FIG. 9 illustrates an example of an energy storage system according toone embodiment of the invention. Energy storage system 413 may performseveral functions. First, it may store energy produced by powerproduction system 103. Energy storage system may use any type of energystorage device such as lead acid batteries, nickel cadmium batteries,metal hydride batteries, a high speed motor which stores electricalenergy as rotational mechanical energy, a large capacitor bank, or amotor compressor which stores energy in the form of compressed air anduses a turbine to convert the energy back to electrical form. It shouldbe appreciated that any type of energy storage device may be used andthe invention is not limited in this regard. Second, the energy storagesystem supplies power to power supply subsystem 415. Sometimes, theinternal power source takes a while to reach its designated output powerlevel. For example, a fuel cell may take some time before it is broughtto full power. Thus, energy storage subsystem 413 provides power topower supply subsystem 415 while the power source is started up andbuffers the power received from the power source so that power supplysubsystem 415 receives a smooth and continuous flow of power. Anotherfunction provided by the energy storage system is buffering a wide DCvoltage range generated by the power production device to a more narrowDC voltage range suitable for the power supply subsystem. Anotherfunction that may be provided by the energy storage system is conversionof DC voltage to an AC voltage. Power supply subsystem 415 includesswitching and voltage regulation for final power conditioning as neededby COTS electronics. Control system 105 may monitor how much energy isstored and direct energy to and from energy storage system 413 throughswitching network 603. Power input 407 allows storage of energy wheninternally generated power is not available.

Power supply system 415 supplies power to enclosure 109 for poweringelectronic devices housed in the enclosure and provides power toenvironmental controls 107 for powering controls, such as compressors,pumps or fans, which use electricity. As shown in FIG. 10, power supplysystem 415 also performs voltage regulation of power received from anenergy source 909. Energy source 909 may be, for example, an energystorage subsystem 413, an external power source 113, or a fuel cellstack 501. Switching subsystem 603 may be used to route the powerproduced by the various sources to subsystems which require power, asdirected by the SECU control system 105. For example, power supplysubsystem 415 may receive, for example, a voltage between 38 and 60volts from the fuel cell stack of power production subsystem 103, anexternal power source, or energy storage subsystem. Switching regulator901 may convert the input voltage to 48 volts DC. Voltage regulator 903may be used to maintain a smooth supply voltage. Voltage regulator 903may also be used to keep the supply voltage within tolerances whenelectrical loads are switched on and off. For example, starting anelectric motor can cause a sudden current inrush, which will diminish asthe motor comes up to rotational speed. Voltage across the motor may dipmomentarily as a result of this inrush of current. Power supply system415 may also include current limiters 905, such as fuses or circuitbreakers to prevent damage to devices in environmental controls 107 orin enclosure 109.

Environmental controls 107 includes mechanical controls which are usedto control the environmental conditions of enclosure 109. For example,environmental controls 107 may include a conditioned air supply system500, shown in FIG. 11, which provides air to the fuel cell stack andenclosure 109. If the temperature of the outside air can safely coolenclosure 109, that air may enter enclosure 109 directly, bypassingconditioned air supply system 500. Air purification, compression,heating, and cooling block 509 serves to adjust the temperature of theair using a heat pump 505. Heat pump 505 may be a reversible heat pumpso that incoming air may be either heated or cooled. Alternatively,waste heat generated by the fuel cell stack or the fuel reformer may beused to heat the air. This waste heat may be used in conjunction withthe heat pump to control temperature of the air. The standardoperational profile may include quantities of waste thermal energyexpected to be generated by the fuel cell stack and fuel reformer at aparticular power level. This data may be used in deciding when and forhow long the heat pump should operate. It should be appreciated thatCOTS electronics may need to be cooled during the course of operation,as excess heat is produced. In the situation where the SECU is used inwinter or arctic-like conditions, then the heat produced may not besufficient to keep the COTS equipment at operational temperature. Inthis situation, the SECU controller 105 may anticipate the needed heatand arrange the component subsystems for efficient transfer of wasteheat to the COTS electronics.

Block 509 also includes a series of filters to remove elements, such assulfur compounds and carbon monoxide, that may be harmful to the fuelcell stack. Air may be stored in air storage reservoir 507 for use bythe fuel cell stack and enclosure 109. Because air may need to beconditioned differently for the fuel cell stack and enclosure 109, airstorage reservoir 507 may have sub-enclosures within the main storagereservoir for air designated for the fuel cell stack. Alternatively,temperature of air in enclosure 109 may be controlled using an isolatedheat exchanger, as described by Vos, et. al., in U.S. Pat. No.6,330,152. Humidification reservoir 511 may store water to humidify theair. Humidification reservoir 511 may be controlled by control system105 to add humidity to air in either block 509 air storage reservoir507. Pressure regulator 503 is under the control of control system 105and regulates the pressure of the air going to fuel cell stack 501 andenclosure 109. Such pressure regulation may be particularly useful when,for example, the SECU is used at high elevations (e.g., in airplanes).

Having thus described illustrative embodiments of the invention, variousmodifications and improvements will readily occur to those skilled inthe art and are intended to be within the scope of the invention.According, the foregoing description is by way of example only and isnot intended as limiting. The invention is limited only as defined inthe following claims and the equivalents thereto.

1. A portable apparatus for housing an electronic device, comprising: anenvironmentally sealed chamber having environmental conditions, whereinthe chamber is adapted to receive the device so that the device isoperable inside the chamber; environmental controls that control theenvironmental conditions; a digital controller for monitoring theenvironmental conditions of the chamber and for selectively activatingand deactivationg the environmental controls to control theenvironmental conditions; and a self contained-power source configuredto provide power to the electronic device, wherein the digitalcontroller is further configured to regulate power generated by theself-contained power source.
 2. The apparatus of claim 1, wherein thesealed chamber is adapted to house at least one of the group comprisingelectronic circuit boards, electronic modules, and electronic units. 3.The apparatus of claim 1, where the digital controller is furtherconfigured to regulate power received from an external power source. 4.The apparatus of claim 1, further comprising a plurality of sensorsconfigured to detect environmental conditions and provide informationregarding the environmental conditions to the digital controller.
 5. Theapparatus of claim 4, wherein the environmental controls includemechanical controls configured to alter environmental conditions insidethe chamber, wherein the mechanical controls are operated under thecontrol of the digital controller based, at least in part, on theinformation received from the plurality of sensors.
 6. The apparatus ofclaim 1, wherein the digital controller is configured to control theenvironmental controls based, at least in part, on a standardoperational profile which specifies desired environmental conditions. 7.The apparatus of claim 1, further comprising an operator interfaceconfigured to provide information from the digital controller to anoperator through an input/output device and to allow an operator tomonitor and control the apparatus.
 8. The apparatus of claim 7, whereinthe operator interface further comprises a data network interfaceconfigured to allow the operator to remotely monitor and control theapparatus.
 9. A method for housing an electronic device in a portableapparatus, comprising acts of: providing, in the portable apparatus, anenvironmentally sealed chamber having environmental conditions therein,wherein the chamber is adapted to receive the device so that the deviceis operable inside the chamber; providing, in the portable apparatus,environmental controls that control the environmental conditions;providing, in the portable apparatus, a digital controller formonitoring the environmental conditions of the chamber and forselectively activating and deactivating the environmental controls tocontrol the environmental Conditions; and providing a self-containedpower source configured to generate power for controlling theenvironmental conditions of the chamber, wherein the digital controllerregulates power generated by the self-contained power source.
 10. Themethod of claim 9, where the digital controller regulates power receivedfrom an external power source.
 11. The method of claim 9, furthercomprising an act of providing a plurality of sensors configured todetect environmental conditions and provide information regarding theenvironmental conditions to the digital controller.
 12. A method forhousing an electronic device in a portable apparatus, comprising:housing an electronic device in an environmentally sealed chamber of theportable apparatus, the chamber having environmental conditions therein,wherein the device is operable inside the chamber; controlling theenvironmental conditions using environmental controls; monitoring theenvironmental conditions and selectively activating and deactivating theenvironmental controls using a digital controller to control theenvironmental condition; and providing a self-contained power sourceconfigured to generate power for controlling the environmentalconditions of the chamber, wherein the digital controller regulatespower generated by the self-contained power source.
 13. The method ofclaim 12, further comprising an act of using a self-contained fuelsource to provide power for controlling the envirotmental controls andfor powering the electronic device.
 14. The method of claim 13, furthercomprising an act of regulating the power generated by theself-contained fuel source.
 15. The method of claim 13, furthercomprising an act of storing unused power generated by self-containedfuel source.
 16. The method of claim 12, further comprising an act ofadjusting the environmental conditions inside the chamber based, atleast in part, on input received from a plurality of sensors inside thechamber.